Embolization of Musculoskeletal Bone Tumors

Abstract

Bone tumors may present as incidental findings, with pain or loss of function, or as fractures. There is a broad range of indications for transarterial embolization (TAE) in primary or metastatic bone tumors: to reduce operative hemorrhagic risks, to simplify or allow more definitive surgery, or in the context of pain palliation, fever, bleeding, or hypercalcemic and other rheological factors. Embolization may also increase tumor sensitivity to chemotherapy or radiation therapy. The procedure itself is often complex with significant risk to adjacent structures and is usually part of a wider treatment strategy. There are many options of embolic agent, techniques, and end points but all aim to devascularize the tumor. Catheter angiography at the time of TAE is used to determine the correct embolic agent and technique with care taken to isolate at risk structures. Many factors determine the best choice of embolic material, probably the most important of which is operator experience. In life-threatening situations or in preoperative embolizations of metastatic tumors, many operators opt for a combination of particulate emboli and stainless steel or platinum coils. Agents discussed include polyvinyl alcohol particles, trisacryl microspheres, gelatin sponge, liquid embolic agents, and embolization coils. Tumor types treated include vascular metastatic lesions, commonly renal cell or thyroid, particularly in locations prone to fracture; giant cell tumors; aneurysmal bone cysts; vertebral hemangiomas, osteosarcomas; arteriovenous malformations; and osteoblastomas. TAE should be considered in the treatment algorithm of primary or secondary bone tumors. Specific benefit is present where there is a high risk of bleeding at surgery, where there is spinal involvement and neural encroachment, where active bleeding is present or in awkward surgical locations where prolonged surgery is anticipated. KEYWORDS: Embolization, bone tumors, metastasesObjectives: Upon completion of this article, the reader should be able to identify which primary or metastatic bone tumors are amenable to embolization and which factors and locations influence the procedural technique and associated risks. The reader should also be able to identify procedures and techniques to increase efficacy and reduce risk as well as be able to choose the correct embolic material. Accreditation: Tufts University School of Medicine (TUSM) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Credit: TUSM designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit TM . Physicians should only claim credit commensurate with the extent of their participation in the activity.

Epithelioid haemangioendothelioma of the scapula in a child: A case report and review of the literature

“…Tumour types treated include metastatic lesions, giant cell tumours, aneurysmal bone cysts, vertebral haemangiomas, osteosarcomas and arterio-venous malformations. 16 Lower operative blood loss and the decreased need for intra-operative transfusion were advantages in the excision of the tumour in this patient.…”

“…[14][15][16] It reduces vascularity and intra-operative blood loss thereby allowing for better definition of tissue planes, and assisting in complete excision during surgery. The principles of TAE of bone tumours are the precise targeting of the occlusive embolic material to the tumour-feeding vessels.…”

Is Pre-Operative Angio-Embolisation an Effective Modality to Control Intraoperative Blood Loss in Extremity Bone Tumors?

“…Ideally an embolic agent will block very small vessels within the tumor but spare the adjacent normal tissue. Relatively larger particulate agents like polyvinyl alcohol (PVA) and Gel foam do not penetrate deeper regions of the tumor but are less likely to cause damage to adjacent normal tissues (1,7,8) . Liquid embolic agents such as acrylic or ethanol and powdered particulate materials can penetrate the smallest of blood vessels but can also damage normal tissues extensively if the vessel identification is faulty (7,8,9) .…”

Preoperative embolization of primary bone tumors: A case control study

“…They present in several ways, like bone destruction, expansion or, infiltration of periosteum. Bone tumors may be detected as an incidental finding or the patient may present with pain or loss of function, or with a pathological fracture [2] . Though there are many treat ment modalities for bone tumors, surgical excision is the treatment of choice and may be coupled with other adjunctive therapies.…”

“…It also reduces the need for blood transfusion and decreases the incidence of complications associated with surgery. TAE allows better definition of tissue planes at surgery leading to complete excision of the bone tumor, which ultimately leads to decrease tumor recurrence rates [2,3] . Refinement of angiographic techniques and advances in hardwares led to its use in preoperative embolization of both primary and secondary bone tumors [4,5] .…”